I cannot find the answer to this. I know there is someone on here that actually knows.
A 351w, and a 302 non ho have different firing orders. The wiring harnesses are near identical. How does the correct batch of injectors get fired at the right time, and is that different at the ecm. Does the ecm pulse the batches different between a 351 and 302 firing order, or are the injectors pulsed multiple times per crank rotation?

 

No.

Injectors are fired on every power stroke.

 

Thank you! Since the injectors only fire once. How can the computers batch pulse the injectors at the same time between 302 351w firing order. I know it fires the same injectors but am I mistaking that they would be pulsed at a different time between 351 / 302?

 

If the injectors are banked 4 in the middle and 4 on the outside corners it just seems the pulse timing or phasing would have to be different to run the two different firing orders. Not trying to be ignorant.... I am really just trying to comprehend how the firing order uses different cylinders in a different order timed on different banks and is the same on and off time. Ugh

 

If you compare the firing orders you'll see they really aren't that different. 13726548 vs 15426378. Injectors are fired in batches of 4 on every power stroke which means all 8 holes get a fresh squirt every crank rotation, some of these squirts don't correspond exactly with an intake valve opening but that doesn't seem to affect things much.

 

Most of the fuel charge is fired against a closed intake valve with a batch fire engine. The engine really doesn't care that much.

The biggest benefit to sequential injection is improved idle quality, and improved idle/low speed emissions.

 

ok I can believe that. Your saying it fires each batch every crank rotation , or every cam? Knowing that Ford used one narrow vain on the distributor I still cant help but wander if the pulses start at a different time. Humor me and write the firing orders out, and circle the batches that are fired. 15426378 13726548 circling 1458 and 2367 you can see they occur at a different time in the 720 degree cycle and following the firing order they occure in a different injector batch. This is what is confusing me.... and why did Ford make one narrow vane if it didn't matter. Sorry not arguing. I promise. I am asking because it doesn't make sense to me, and I know you guys have more experience by far. That is why I am asking here.

 

Oh that matters.. the computer still wants to know when piston #1 is at TDC.

 

The PIP signal also triggers when the ignition fires. The computer needs to know where Cylinder #1 is in order to run the engine from a spark firing perspective.. As previously stated multiple times the fuel system is a different story because the injectors are fired in batches.